1. Field of the Invention
The present invention relates to a building block comprising spaced apart outer and inner walls made of hard moldable material such as concrete and interconnected through tie members.
2. Brief Description of the Prior Art
Many building blocks of the above type have been proposed in the prior art. Such building blocks usually comprise outer and inner concrete walls which are spaced apart from each other but interconnected through at least two tie members. Examples are illustrated and described in U.S. Pat. No. 783,452 (Morenus) issued on Feb. 28, 1905, in U.S. Pat. No. 1,448,648 granted to H. Wilkins on Mar. 13, 1923, in U.S. Pat. No. 1,778,881 (Alford) granted on Oct. 21, 1930, and in in the name of DeLuca et al.
All these prior art building blocks present a common major drawback. After a wall has been erected with these blocks, they do not enable easy nailing and/or screwing upon finishing of the inside of the so erected wall.